Implementation of removable fluid pathway joints using gaskets is well known. Early examples include the connection of pipe segments described in the 1920's work of the American Standards Association (ASA B16e-1932) which has been updated and expanded over many years to the present American Society of Mechanical Engineers standard for Pipe Flanges and Flanged Fittings (ASME B16.5-2009). In some situations it is desired to have a subassembly comprising a gasket positioned by a locating part to ensure correct assembly of the joint. U.S. Pat. No. 3,857,572 issued to Taylor and Halling discloses one such example and U.S. Pat. No. 6,409,180 issued to Spence and Felber discloses a more recent example.
Representative fluid delivery apparatus are found, for example, among industrial equipment producing fine chemicals, petroleum products, or semiconductors, and may be subjected to vacuum, or pressure, or purity requirements, and combinations thereof. Fluid pathways among elements intended for manipulating process materials within semiconductor manufacturing equipment usually require attention to maintaining high purity of the delivered reactants and also typically have a much smaller cross-section than fluid pathways used in petrochemical plants, for example. Fluid delivery systems for semiconductor manufacturing equipment typically use surface mount components removably attached to substrates containing fluid pathways. The interface between each component and substrate is generally planar with fluid conduit ports having structural details dependent upon the specific seal design. Example systems are disclosed in U.S. Pat. No. 6,068,016 issued to Manofsky and Fittro, and also U.S. Pat. Nos. 5,992,463 and 6,394,138, both issued to the present inventor Kim Ngoc Vu, et al.
A known fluid pathway joint (familiarly called the C-seal joint type) uses a ring-shaped metallic gasket of complex shape compressed between opposing apparatus elements wherein the face of at least one element has a circular counterbore depression to receive the gasket. In some implementations a separate retainer is provided for holding and centering the gasket during joint assembly whereby the retainer engages a cavity or groove on the periphery of the gasket. The retainer illustrated in the previously mentioned Manofsky—'016 system example may be seen individually in U.S. Pat. No. 5,713,582, issued to Swensen, et al. Another counterbore gasket with separate retainer is disclosed in U.S. Pat. No. 5,797,604 issued to Inagaki, et al, and that retainer may be seen individually in U.S. Pat. No. 5,984,318 issued to Kojima and Aoyama. Yet another counterbore gasket with separate retainer is disclosed in U.S. Pat. No. 5,771,919 issued to Itoi, et al. An additional separate retainer for C-seal type joints is disclosed in U.S. Pat. No. 6,845,984 issued to Doyle, another retainer is disclosed in U.S. Pat. No. 6,945,539 issued to Whitlow, et al, and yet another retainer commercially available from Microflex Technologies (Anaheim, Calif.; www.microflexseals.com) is illustrated in FIG. 4 of this application.
The foregoing retainer designs use thin flat sheet metal as the basic material of construction and engage a cavity or groove on the outside diameter periphery of a gasket. A related but nonmetallic retainer is disclosed in U.S. Pat. No. 5,730,448 issued to Swensen, et al, wherein a circumferential recess of the gasket is engaged by a resilient element. U.S. Pat. No. 7,126,094, issued to Bower and Chase, discloses a flat heater comprised of metallic resistance material and insulating plastic together forming a structure which may simultaneously serve as a retainer for C-seal gaskets. U.S. Pat. No. 6,474,700, issued to the present inventor Kim Ngoc Vu, et al, discloses a retainer that overlaps peripheral projections of a Z-seal gasket (one known variant of a gasket shearing type of seal arrangement) instead of engaging the circumferential groove of a C-seal gasket.
Illustrated in FIG. 4 is a plan view of a prior art retainer design 400 commercially available from Microflex Technologies of Anaheim, Calif., for use with a two-port surface mount K1S style fluid delivery component. The prior art retainer 400 is made from a thin flat square member 410 of stainless steel sheet metal having two circular gasket-capturing apertures 440, 444 for use with known C-seal gaskets (not shown), and four fastener apertures 431, 432, 437, 438 in locations corresponding to the corner mounting holes of a fluid delivery component of square shape approximately 1.115-inch by 1.115-inch. Each gasket-capturing aperture 440, 444 has two cantilevered projections (a total of four projections in the case of a two-gasket retainer as illustrated) 450, 460, 454, 464 appearing similar to triangular points. Each generally triangular projection is formed by a straight slot, intersecting tangentially to the perimeter of each gasket-capturing aperture, defining one side and an intersected arc segment forming another side, and each triangle base being contiguous with the remainder of the square member 410. An intervening web of material 480 makes one gasket-capturing aperture 440 distinct from the other aperture 444. Each fastener aperture 431, 432, 437, 438 has three cantilevered tabs intended to engage external threads passing through. Designers should thus appreciate that the prior art retainer 400 has many small sharp locally convex features prone to snagging during handling.
The retainers illustrated in Swensen—'582, Doyle—'984, the Microflex Technologies item as FIG. 4 herein, and Swensen—'448, all use cantilevered portions of the retainer to engage a cavity or groove on the outside diameter periphery of each of one or more C-seal type gaskets. The cantilevered portions of such retainers have several relatively sharp projecting corners, are consequently delicate and prone to handling damage, and require manufacturing processes capable of forming thin arms or narrow slots. Additionally, the retainer illustrated in Whitlow-'539 has relatively sharp corners at its “interference region” and needs close dimensional tolerances to correctly hold a gasket by engaging a peripheral groove.